Anomalous posterior semicircular canals in congenital hearing loss: not-so-common findings in a common imaging scenario!

BACKGROUND

Congenital SNHL cases often undergo imaging to rule out malformations of the inner ear. Semicircular (SCC) anomalies constitute one such important group with posterior SCC being rarely affected. We describe a radiological spectrum of anomalous posterior SCCs in three cases with congenital SNHL. CASE FINDINGS: All three cases were children < 14 years of age and underwent HRCT and MRI with a variable degree of anomalies affecting the posterior SCC. The first case had aplasia of left post SCC with findings of Type I Incomplete partition. Second case showed isolated posterior SCC hypoplasia bilaterally with no other inner ear malformation on imaging. Third case revealed findings of a dysplastic left posterior SCC with features of Type I Incomplete partition. DISCUSSION: These three cases represent a unique imaging spectrum resulting from an arrest at various stages of embryological development of post SCC. These anomalies often accompanyother inner ear malformations (IEMs) and systemic syndromes.

CONCLUSION

Comprehensive imaging with CT and MRI is essential to determine the presence and degree of IEMs as well as to ascertain the status of cochlear nerve in determining feasibility for cochlear implantation.